widget.py
449 lines
| 16.1 KiB
| text/x-python
|
PythonLexer
|
r14586 | """Base Widget class. Allows user to create widgets in the back-end that render | ||
in the IPython notebook front-end. | ||||
|
r14283 | """ | ||
#----------------------------------------------------------------------------- | ||||
# Copyright (c) 2013, the IPython Development Team. | ||||
# | ||||
# Distributed under the terms of the Modified BSD License. | ||||
# | ||||
# The full license is in the file COPYING.txt, distributed with this software. | ||||
#----------------------------------------------------------------------------- | ||||
#----------------------------------------------------------------------------- | ||||
# Imports | ||||
#----------------------------------------------------------------------------- | ||||
|
r14579 | from contextlib import contextmanager | ||
|
r14223 | |||
|
r15192 | from IPython.core.getipython import get_ipython | ||
|
r14229 | from IPython.kernel.comm import Comm | ||
from IPython.config import LoggingConfigurable | ||||
|
r15368 | from IPython.utils.traitlets import Unicode, Dict, Instance, Bool, List, Tuple, Int | ||
|
r14232 | from IPython.utils.py3compat import string_types | ||
|
r14283 | #----------------------------------------------------------------------------- | ||
# Classes | ||||
#----------------------------------------------------------------------------- | ||||
|
r14658 | class CallbackDispatcher(LoggingConfigurable): | ||
|
r14793 | """A structure for registering and running callbacks""" | ||
callbacks = List() | ||||
def __call__(self, *args, **kwargs): | ||||
"""Call all of the registered callbacks.""" | ||||
|
r14721 | value = None | ||
|
r14793 | for callback in self.callbacks: | ||
try: | ||||
local_value = callback(*args, **kwargs) | ||||
except Exception as e: | ||||
|
r15192 | ip = get_ipython() | ||
if ip is None: | ||||
self.log.warn("Exception in callback %s: %s", callback, e, exc_info=True) | ||||
else: | ||||
ip.showtraceback() | ||||
|
r14793 | else: | ||
|
r14721 | value = local_value if local_value is not None else value | ||
return value | ||||
|
r14658 | |||
def register_callback(self, callback, remove=False): | ||||
"""(Un)Register a callback | ||||
Parameters | ||||
---------- | ||||
callback: method handle | ||||
|
r14793 | Method to be registered or unregistered. | ||
|
r14658 | remove=False: bool | ||
|
r14793 | Whether to unregister the callback.""" | ||
|
r14658 | # (Un)Register the callback. | ||
|
r14793 | if remove and callback in self.callbacks: | ||
self.callbacks.remove(callback) | ||||
elif not remove and callback not in self.callbacks: | ||||
self.callbacks.append(callback) | ||||
|
r14223 | |||
|
r15192 | def _show_traceback(method): | ||
"""decorator for showing tracebacks in IPython""" | ||||
def m(self, *args, **kwargs): | ||||
try: | ||||
return(method(self, *args, **kwargs)) | ||||
except Exception as e: | ||||
ip = get_ipython() | ||||
if ip is None: | ||||
self.log.warn("Exception in widget method %s: %s", method, e, exc_info=True) | ||||
else: | ||||
ip.showtraceback() | ||||
return m | ||||
|
r14658 | |||
class Widget(LoggingConfigurable): | ||||
|
r14653 | #------------------------------------------------------------------------- | ||
# Class attributes | ||||
#------------------------------------------------------------------------- | ||||
|
r14793 | _widget_construction_callback = None | ||
|
r14586 | widgets = {} | ||
|
r14478 | |||
|
r14793 | @staticmethod | ||
|
r14478 | def on_widget_constructed(callback): | ||
|
r14793 | """Registers a callback to be called when a widget is constructed. | ||
|
r14607 | |||
The callback must have the following signature: | ||||
|
r14478 | callback(widget)""" | ||
|
r14793 | Widget._widget_construction_callback = callback | ||
|
r14478 | |||
|
r14793 | @staticmethod | ||
|
r14542 | def _call_widget_constructed(widget): | ||
|
r14793 | """Static method, called when a widget is constructed.""" | ||
if Widget._widget_construction_callback is not None and callable(Widget._widget_construction_callback): | ||||
Widget._widget_construction_callback(widget) | ||||
|
r14478 | |||
|
r14653 | #------------------------------------------------------------------------- | ||
# Traits | ||||
#------------------------------------------------------------------------- | ||||
|
r14896 | _model_name = Unicode('WidgetModel', help="""Name of the backbone model | ||
|
r14586 | registered in the front-end to create and sync this widget with.""") | ||
|
r14701 | _view_name = Unicode(help="""Default view registered in the front-end | ||
|
r14588 | to use to represent the widget.""", sync=True) | ||
|
r14486 | _comm = Instance('IPython.kernel.comm.Comm') | ||
|
r14793 | |||
|
r15368 | msg_throttle = Int(3, sync=True, help="""Maximum number of msgs the | ||
front-end can send before receiving an idle msg from the back-end.""") | ||||
|
r14793 | |||
keys = List() | ||||
def _keys_default(self): | ||||
return [name for name in self.traits(sync=True)] | ||||
_property_lock = Tuple((None, None)) | ||||
_display_callbacks = Instance(CallbackDispatcher, ()) | ||||
_msg_callbacks = Instance(CallbackDispatcher, ()) | ||||
|
r14653 | #------------------------------------------------------------------------- | ||
# (Con/de)structor | ||||
|
r14793 | #------------------------------------------------------------------------- | ||
|
r14310 | def __init__(self, **kwargs): | ||
|
r14607 | """Public constructor""" | ||
|
r14540 | super(Widget, self).__init__(**kwargs) | ||
|
r14478 | |||
|
r14487 | self.on_trait_change(self._handle_property_changed, self.keys) | ||
|
r14542 | Widget._call_widget_constructed(self) | ||
|
r14485 | |||
|
r14223 | def __del__(self): | ||
|
r14283 | """Object disposal""" | ||
|
r14223 | self.close() | ||
|
r14485 | |||
|
r14653 | #------------------------------------------------------------------------- | ||
# Properties | ||||
|
r14793 | #------------------------------------------------------------------------- | ||
|
r14586 | |||
|
r14485 | @property | ||
def comm(self): | ||||
|
r14654 | """Gets the Comm associated with this widget. | ||
If a Comm doesn't exist yet, a Comm will be created automagically.""" | ||||
|
r14485 | if self._comm is None: | ||
|
r14586 | # Create a comm. | ||
|
r14896 | self._comm = Comm(target_name=self._model_name) | ||
|
r14586 | self._comm.on_msg(self._handle_msg) | ||
Widget.widgets[self.model_id] = self | ||||
# first update | ||||
self.send_state() | ||||
|
r14485 | return self._comm | ||
|
r14512 | |||
@property | ||||
def model_id(self): | ||||
|
r14654 | """Gets the model id of this widget. | ||
If a Comm doesn't exist yet, a Comm will be created automagically.""" | ||||
|
r14527 | return self.comm.comm_id | ||
|
r14485 | |||
|
r14653 | #------------------------------------------------------------------------- | ||
# Methods | ||||
|
r14793 | #------------------------------------------------------------------------- | ||
|
r14653 | def close(self): | ||
|
r14793 | """Close method. | ||
|
r14232 | |||
|
r17405 | Closes the underlying comm. | ||
|
r14653 | When the comm is closed, all of the widget views are automatically | ||
removed from the front-end.""" | ||||
|
r17465 | del Widget.widgets[self.model_id] | ||
|
r15702 | if self._comm is not None: | ||
|
r14793 | self._comm.close() | ||
|
r17479 | self._comm = None | ||
|
r17465 | |||
|
r14283 | def send_state(self, key=None): | ||
|
r14586 | """Sends the widget state, or a piece of it, to the front-end. | ||
|
r14283 | |||
Parameters | ||||
---------- | ||||
key : unicode (optional) | ||||
|
r14586 | A single property's name to sync with the front-end. | ||
|
r14283 | """ | ||
|
r14610 | self._send({ | ||
"method" : "update", | ||||
"state" : self.get_state() | ||||
}) | ||||
|
r14283 | |||
|
r14486 | def get_state(self, key=None): | ||
|
r14485 | """Gets the widget state, or a piece of it. | ||
|
r14283 | |||
Parameters | ||||
---------- | ||||
|
r14485 | key : unicode (optional) | ||
A single property's name to get. | ||||
|
r14283 | """ | ||
|
r14586 | keys = self.keys if key is None else [key] | ||
|
r17237 | state = {} | ||
for k in keys: | ||||
|
r17328 | f = self.trait_metadata(k, 'to_json') | ||
|
r17294 | if f is None: | ||
|
r17328 | f = self._trait_to_json | ||
|
r17294 | value = getattr(self, k) | ||
state[k] = f(value) | ||||
|
r17237 | return state | ||
|
r14387 | def send(self, content): | ||
"""Sends a custom msg to the widget model in the front-end. | ||||
Parameters | ||||
---------- | ||||
content : dict | ||||
Content of the message to send. | ||||
""" | ||||
|
r14655 | self._send({"method": "custom", "content": content}) | ||
|
r14387 | |||
|
r14586 | def on_msg(self, callback, remove=False): | ||
|
r14793 | """(Un)Register a custom msg receive callback. | ||
|
r14387 | |||
Parameters | ||||
---------- | ||||
|
r14793 | callback: callable | ||
|
r14915 | callback will be passed two arguments when a message arrives:: | ||
|
r14793 | callback(widget, content) | ||
|
r14915 | |||
|
r14387 | remove: bool | ||
True if the callback should be unregistered.""" | ||||
|
r14658 | self._msg_callbacks.register_callback(callback, remove=remove) | ||
|
r14387 | |||
|
r14330 | def on_displayed(self, callback, remove=False): | ||
|
r14607 | """(Un)Register a widget displayed callback. | ||
|
r14330 | |||
|
r14332 | Parameters | ||
---------- | ||||
|
r14330 | callback: method handler | ||
|
r14915 | Must have a signature of:: | ||
|
r14793 | callback(widget, **kwargs) | ||
|
r14915 | |||
|
r14793 | kwargs from display are passed through without modification. | ||
|
r14330 | remove: bool | ||
True if the callback should be unregistered.""" | ||||
|
r14658 | self._display_callbacks.register_callback(callback, remove=remove) | ||
|
r14330 | |||
|
r14653 | #------------------------------------------------------------------------- | ||
|
r14283 | # Support methods | ||
|
r14653 | #------------------------------------------------------------------------- | ||
@contextmanager | ||||
|
r14659 | def _lock_property(self, key, value): | ||
|
r14653 | """Lock a property-value pair. | ||
NOTE: This, in addition to the single lock for all state changes, is | ||||
flawed. In the future we may want to look into buffering state changes | ||||
back to the front-end.""" | ||||
self._property_lock = (key, value) | ||||
try: | ||||
yield | ||||
finally: | ||||
self._property_lock = (None, None) | ||||
def _should_send_property(self, key, value): | ||||
"""Check the property lock (property_lock)""" | ||||
return key != self._property_lock[0] or \ | ||||
value != self._property_lock[1] | ||||
# Event handlers | ||||
|
r15192 | @_show_traceback | ||
|
r14653 | def _handle_msg(self, msg): | ||
"""Called when a msg is received from the front-end""" | ||||
data = msg['content']['data'] | ||||
method = data['method'] | ||||
if not method in ['backbone', 'custom']: | ||||
self.log.error('Unknown front-end to back-end widget msg with method "%s"' % method) | ||||
# Handle backbone sync methods CREATE, PATCH, and UPDATE all in one. | ||||
if method == 'backbone' and 'sync_data' in data: | ||||
sync_data = data['sync_data'] | ||||
self._handle_receive_state(sync_data) # handles all methods | ||||
# Handle a custom msg from the front-end | ||||
elif method == 'custom': | ||||
|
r14655 | if 'content' in data: | ||
self._handle_custom_msg(data['content']) | ||||
|
r14653 | |||
def _handle_receive_state(self, sync_data): | ||||
"""Called when a state is received from the front-end.""" | ||||
for name in self.keys: | ||||
if name in sync_data: | ||||
|
r17328 | f = self.trait_metadata(name, 'from_json') | ||
|
r17294 | if f is None: | ||
|
r17328 | f = self._trait_from_json | ||
|
r17294 | value = f(sync_data[name]) | ||
|
r14659 | with self._lock_property(name, value): | ||
|
r14653 | setattr(self, name, value) | ||
def _handle_custom_msg(self, content): | ||||
"""Called when a custom msg is received.""" | ||||
|
r14793 | self._msg_callbacks(self, content) | ||
|
r14653 | |||
def _handle_property_changed(self, name, old, new): | ||||
"""Called when a property has been changed.""" | ||||
# Make sure this isn't information that the front-end just sent us. | ||||
if self._should_send_property(name, new): | ||||
# Send new state to front-end | ||||
self.send_state(key=name) | ||||
def _handle_displayed(self, **kwargs): | ||||
"""Called when a view has been displayed for this widget instance""" | ||||
|
r14793 | self._display_callbacks(self, **kwargs) | ||
|
r14653 | |||
|
r17328 | def _trait_to_json(self, x): | ||
"""Convert a trait value to json | ||||
|
r14653 | |||
|
r17237 | Traverse lists/tuples and dicts and serialize their values as well. | ||
Replace any widgets with their model_id | ||||
""" | ||||
|
r14656 | if isinstance(x, dict): | ||
|
r17328 | return {k: self._trait_to_json(v) for k, v in x.items()} | ||
|
r15465 | elif isinstance(x, (list, tuple)): | ||
|
r17328 | return [self._trait_to_json(v) for v in x] | ||
|
r14656 | elif isinstance(x, Widget): | ||
|
r17262 | return "IPY_MODEL_" + x.model_id | ||
|
r14653 | else: | ||
|
r14657 | return x # Value must be JSON-able | ||
|
r14653 | |||
|
r17328 | def _trait_from_json(self, x): | ||
|
r17237 | """Convert json values to objects | ||
|
r14653 | |||
|
r17328 | Replace any strings representing valid model id values to Widget references. | ||
|
r17237 | """ | ||
|
r14656 | if isinstance(x, dict): | ||
|
r17328 | return {k: self._trait_from_json(v) for k, v in x.items()} | ||
|
r15465 | elif isinstance(x, (list, tuple)): | ||
|
r17328 | return [self._trait_from_json(v) for v in x] | ||
|
r17262 | elif isinstance(x, string_types) and x.startswith('IPY_MODEL_') and x[10:] in Widget.widgets: | ||
|
r17237 | # we want to support having child widgets at any level in a hierarchy | ||
# trusting that a widget UUID will not appear out in the wild | ||||
return Widget.widgets[x] | ||||
|
r14653 | else: | ||
|
r14656 | return x | ||
|
r14653 | |||
|
r14586 | def _ipython_display_(self, **kwargs): | ||
|
r14607 | """Called when `IPython.display.display` is called on the widget.""" | ||
|
r14548 | # Show view. By sending a display message, the comm is opened and the | ||
# initial state is sent. | ||||
|
r14549 | self._send({"method": "display"}) | ||
|
r14485 | self._handle_displayed(**kwargs) | ||
|
r14479 | |||
def _send(self, msg): | ||||
|
r14607 | """Sends a message to the model in the front-end.""" | ||
|
r14548 | self.comm.send(msg) | ||
|
r14516 | |||
|
r14540 | class DOMWidget(Widget): | ||
|
r14793 | visible = Bool(True, help="Whether the widget is visible.", sync=True) | ||
|
r16816 | _css = List(sync=True) # Internal CSS property list: (selector, key, value) | ||
|
r14485 | |||
def get_css(self, key, selector=""): | ||||
|
r14581 | """Get a CSS property of the widget. | ||
Note: This function does not actually request the CSS from the | ||||
front-end; Only properties that have been set with set_css can be read. | ||||
|
r14485 | |||
Parameters | ||||
---------- | ||||
key: unicode | ||||
CSS key | ||||
selector: unicode (optional) | ||||
JQuery selector used when the CSS key/value was set. | ||||
""" | ||||
if selector in self._css and key in self._css[selector]: | ||||
return self._css[selector][key] | ||||
else: | ||||
return None | ||||
|
r14793 | def set_css(self, dict_or_key, value=None, selector=''): | ||
|
r14581 | """Set one or more CSS properties of the widget. | ||
This function has two signatures: | ||||
|
r14551 | - set_css(css_dict, selector='') | ||
- set_css(key, value, selector='') | ||||
|
r14485 | |||
Parameters | ||||
---------- | ||||
css_dict : dict | ||||
CSS key/value pairs to apply | ||||
key: unicode | ||||
CSS key | ||||
|
r14793 | value: | ||
|
r14485 | CSS value | ||
|
r14793 | selector: unicode (optional, kwarg only) | ||
|
r14581 | JQuery selector to use to apply the CSS key/value. If no selector | ||
is provided, an empty selector is used. An empty selector makes the | ||||
front-end try to apply the css to a default element. The default | ||||
element is an attribute unique to each view, which is a DOM element | ||||
of the view that should be styled with common CSS (see | ||||
`$el_to_style` in the Javascript code). | ||||
|
r14485 | """ | ||
|
r14793 | if value is None: | ||
css_dict = dict_or_key | ||||
|
r14485 | else: | ||
|
r14793 | css_dict = {dict_or_key: value} | ||
for (key, value) in css_dict.items(): | ||||
|
r16816 | # First remove the selector/key pair from the css list if it exists. | ||
# Then add the selector/key pair and new value to the bottom of the | ||||
# list. | ||||
self._css = [x for x in self._css if not (x[0]==selector and x[1]==key)] | ||||
self._css += [(selector, key, value)] | ||||
|
r14793 | self.send_state('_css') | ||
|
r14485 | |||
|
r14539 | def add_class(self, class_names, selector=""): | ||
|
r14607 | """Add class[es] to a DOM element. | ||
|
r14485 | |||
Parameters | ||||
---------- | ||||
|
r14539 | class_names: unicode or list | ||
Class name(s) to add to the DOM element(s). | ||||
|
r14485 | selector: unicode (optional) | ||
JQuery selector to select the DOM element(s) that the class(es) will | ||||
be added to. | ||||
""" | ||||
|
r14539 | class_list = class_names | ||
|
r15465 | if isinstance(class_list, (list, tuple)): | ||
|
r14539 | class_list = ' '.join(class_list) | ||
|
r14610 | self.send({ | ||
"msg_type" : "add_class", | ||||
"class_list" : class_list, | ||||
"selector" : selector | ||||
}) | ||||
|
r14485 | |||
|
r14539 | def remove_class(self, class_names, selector=""): | ||
|
r14607 | """Remove class[es] from a DOM element. | ||
|
r14485 | |||
Parameters | ||||
---------- | ||||
|
r14539 | class_names: unicode or list | ||
Class name(s) to remove from the DOM element(s). | ||||
|
r14485 | selector: unicode (optional) | ||
JQuery selector to select the DOM element(s) that the class(es) will | ||||
be removed from. | ||||
""" | ||||
|
r14539 | class_list = class_names | ||
|
r15465 | if isinstance(class_list, (list, tuple)): | ||
|
r14539 | class_list = ' '.join(class_list) | ||
|
r14610 | self.send({ | ||
"msg_type" : "remove_class", | ||||
"class_list" : class_list, | ||||
"selector" : selector, | ||||
}) | ||||